A cube shaped charge centered at the origin has uniform

Question

A cube shaped charge centered at the origin has uniform charge density 3.0 mC/m³ and side length 0.2 meter. Use an appropriate theorem to determine the flux of the electric field over a spherical Gaussian surface, also centered at the origin, and of radius

(a) 0.05 m,

(b) 0.1 m, and

(c) 0.5 m.